Additive for hydrocarbon fuels



United States Patent O 3,230,058 ADDITIVE FOR HYDRGCARBON FUELS Harold C. Walters, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Nov. 20, 1961, Ser. No. 153,727 2 Claims. (Cl. 44-66).

This invention relates to an additive for hydrocarbon fuels. In one aspect the invention relates to a hydrocarbon fuel inhibited against static electricity accumulation. In another aspect the invention relates to a method of inhibiting ice formation and static electricity accumulation in volatile hydrocarbon fuels.

Continuing research in the utilization of hydrocarbon fuels as produced improvements in their performance, handling, safety aspects and, in some cases, has reduced the cost of operation. Many of these improvements have been in the form of additives wherein small quantitles of specific compositions are added to the fuel, such as bactericides, anticorrosion agents, deicers, heat stabilizers, storage stabilizers, combustion deposit modi fiers antiknock compounds, scavengers, etc.

Considerable attention has been focused in recent years upon the electrical conductivity properties of hydrocarbon fuels due to a number of explosions which have occurred during the handling of such fuels. Although most of these explosions have taken place while turbojet aircraft fuels were being transferred from one tank to another, there have been instances of explosions occurring while transporting gasolines, kerosenes, solvents and other hydrocarbon products boiling between about 75 and about 750 F. when the ambient temperatures were slightly above the flash points of the products. Turbojet fuels are particularly hazardous because their vapors form explosive mixtures with the air over a relatively wide temperature range.

It has been postulated that these explosions are due to tribo electric discharges. The mechanism involved in explosions of hydrocarbon fuels attributed to tribo electricity are not fully understood; however, it is believed that small concentrations of ionic contaminants play an important role. It has been postulated that ionizable particles in the fuels are attracted to surfaces, such as the sides of fuel tanks and pipe lines, where the movement of the fuel sweeps away some of the particles of opposite polarity thus tending to create an electrical charge on the fuel. Where such a potential reaches a sufliciently high level, electrical energy is discharged and may ignite hydrocarbon vapors present in admixture with air to cause an explosion. This is, of course, only one explanation of the phenomena and there may be other mechanisms involved.

It has been found that hydrocarbon fuels which are void of ionizable contaminants, such as residues, degradation or oxidation products, do not readily become charged. However, such an ultra clean fuel condition is difficult to achieve and maintain in the practical realm. However, it is known that polar materials may increase the conductivity of the fuel to a point where the charge may be safely conducted away. Thus, by adding ionizable materials to the fuel the ability of the fuel to dissipate static charges surpasses the ability to develop them. Such a fuel exhibits a relatively high conductivity and is less likely to cause difiiculty. It has been reported that a dangerous middle ground exists and that a fuel 3,230,058 Ce Patented Jan. 18, 1966 with an intermediate conductivity of IX i0 to 1X10- mho/cm. is capable of becoming dangerously charged. Consequently, a number antistatic additives have been developed which purport to increase the conductivity of fuel to l 10- or greater. Hydrocarbon fuels generally have electrical conductivity in the range of 1 1O- to 1 l() so that not all fuels are necessarily sulbject to turboelectric discharges. However, additives to fuels possessing dangerous conductivity have sometimes been known to degrade other properties of the fuel. Similarly, combinations of two or more additives may also produce unexpected and undesirable side effects. For example, an additive which successfully inhibits bacterial growth in fuel may cause metal corrosion problems and an anticorrosion agent may also adversely effect combustion deposits. In addition, although some additives do markedly increase the conductivity of hydrocarbons, it has been found that their usefulness generally is limited to a very narrow concentration range. If the concentration of such an additive in the fuel oil is inadvertently reduced, there may be a greater danger of explosion than if no additive were present at all.

An important property of a liquid hydrocarbon fuel which is frequently disturbed by the use of fuel additives is its ability to separate from water. Hydrocarbon fuels are frequently unavodably exposed to water or water vapor. Water is a very highly undesirable component in fuels, particularly when used in aircraft engines, for a host of reasons and, consequently, the fuel is passed through filters or water separators which dry the fuel when transferring the fuel from one point to another. The ability of the fuel to separate itself from water determines the efliciency of the water separation stage and is therefore an important fuel property. This property is disturbed when materials having surfactant properties are added to the fuel. Such additives tend to emulsify the water and to prevent its removal by the equipment utilized.

The formation of ice within the fuel system of a jet aircraft has been recognized as a problem for a long time. Flights at high altitudes for long durations often result in the fuel being chilled to temperatures approaching that of the air in which the aircraft are operating. All jet fuel contains small amounts of dissolved and/or entrained water. When the fuel is chilled, the water separates from the fuel and ice is formed. Ice formation in an aircraft fuel system at points of restricted flow such as filters, screens, valves, orifices, etc., is a serious matter because the engine fuel supply may be restricted and certain instruments may not respond correctly. A number of engine flame-outs have been attributed to ice formation in the fuel system.

An anti-icing additive is described in the copending application of James A. Shotton, Serial No. 90,953, filed February 23, 1961, which is a continuation in part of Serial No. 79 filed January 4, 1960. Both applications of James A. Shotton are now abandoned. The additive described therein includes a blend of a saturated acyclic polyhydric alcohol and a glycol ether.

It is an object of this invention to provide a novel additive for hydrocarbon fuels.

It is another object of the invention to provide a novel hydrocarbon fuel composition having improved antistatic properties.

Another object of the invention is to provide a novel method of operating a jet engine with a fuel supply system subject to subfreezing temperatures and static electricity accumulation.

Yet another object of the invention is to provide an improved method of stabilizing a hydrocarbon fuel against ice formation and static electricity accumulation without adversely effecting water separability properties.

These objects are broadly accomplished by a liquid hydrocarbon fuel containing a nitrogenous compound having the formula wherein R is a member of the group consisting of aliphatic and alicyclic hydrocarbon radicals containing at least 7 carbon atoms per molecule, preferably 10 to 20 carbon atoms; R is a member of the group consisting of alkyl and hydroxyal'kyl radicals containing from 1 to 3 carbon atoms, inclusive; R is a member of a group consisting of hydrogen and radicals having the same meaning as R R is a hydroxyalkyl radical containing from 1 to 3 carbon atoms, inclusive; and Y is an anion.

In one aspect, a glycol ether is employed in conjunction with said nitrogenous compound.

In a preferred embodiment, the additive of this invention comprises said nitrogenous compound, a glycol ether and a saturated acyclic polyhydroxy alcohol as hereinafter defined.

A wide variety of monocarboxylic acids may supply R, such as, for example, caprylic acid, decenoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, oleic acid and other highly unsaturated fatty acids of 14 to 18 carbons obtained from vegetable and animal oil and fats such as soy'a bean oil, cotton seed oil, coconut oil, linseed oil, castor oil, dehydrated castor oil and the like, or from other sources such as tall oil. A-licyclic monocanboxylic acids which may be used include petroleum naphthenic acids of 7 to 14 carbon atoms having boiling points within the range of 215 to 310 C., as described in Ellis, Chemistry of Petroleum Derivatives (1934), pages 1062-1085, abietic acid, and the like.

Illustrative examples of radicals represented by R in the aforesaid nitrogenous compound are normal and unbranched heptyl, octyl, octenyl, nonyl, nonenyl, decyl, decenyl, undecyl, undecenyl, tridecyl, tetradecyl, tetradecenyl, heptadecyl, heptadecenyl, octadecyl, octadecenyl, the residue of abietic acid and the like radicals. Illustrative examples of the radical represented by R and R are methyl, ethyl, propyl, isopropyl, hydroxyethyl, dihydroxyp-ropyl, trihydroxypropyl and the like radicals. Illustrative examples of R include hydroxymethy-l, hydroxyethyl, hydroxypropyl, dihydroxypropyl, and the like radicals. Illustrative examples of anions represented by Y are chloride, bromide, fluoride, iodide, sulfate, sulfonate, phosphate, hydroxide, borate, carbonate, hydrocarbonate, isocyanate, nitrate, nitrite, oxalate, acetate, hydrogen sulfate, thiocyanate, sulfite, bisulfi-te, silicate, sulfide, ethylsulfate, and other inorganic and organic ions.

Representative nitrogenous compounds include:

r 11 0 ONEXCH 3-III-CH2CH5OHIHC1" Gainma caprylamidopropyldimethyl beta-hydroxyethyl) ammonium chloride Gamma-stearamidopropyldimethyl (2,3-dihydr0xypropyl) ammonium hydroxide [01 1511 0 ONH (CH 3-N(CH2OH2OH) ]+C O Gamma-s tearamidopropyl-tris (beta-hydroxyethyl) ammonium carbonate Gamma-stearamidopropyldimethyl (beta-hydroxyethyl) ammonium nitrate Gammadauramidopropylmethyl-bis (beta-hydroxyethyl) d ammonium chloride an CH3 Gamma-abietamidopropyldimethyl (beta-hydroxyethyl) ammonium iodide The preferred nitrogenous compound is gamma-steam amid oprop yldimethyl (be ta-hydroxy) ammonium nitrate.

It has been found that a combination of the above-recited nitrogenous compound, a saturated acyclic polyhydroxy alcohol and a glycol ether provides a particularly effective combination for inhibiting the accumulation of static electricity and the formation of ice in the fuel. Moreover, and most important, the effect of this specific combination of compounds on the accumulation of static electricity in the fuel is an improvement over the effect one Would expect based upon the effect exhibited by each individual compound in the fuel. This synergistic effect is also exhibited with regard to water separability.

Therefore, in one aspect of the invention the accumulation of static electricity and ice formation is inhibited by the inclusion of an additive comprising: (1) a blend of (A) a major proportion of a glycol ether having the formula R'(OCH 0H OH, where R is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, phenyl, and tolyl groups, when R is hydrogen, x is 2 to 4, otherwise, x is 1 to 4, and (B) a minor amount of a saturated acyclic polyhydroxy alcohol having 3 to 5 carbon atoms per molecule, from 2 to 5 OH groups each attached to a different carbon and a ratio of hydroxy radicals to carbons in the range of 0.66:1 to 1: 1, said minor amount being sufficient to synergistically increase the antiicing properties of said blend when added to said hydrocarbon fuel; and (2) said hereinbefore-described nitrogenous compound, said nitrogenous compound being present in an amount suflicient to synergistically increase the electrical conductivity of said additive When added to said hydrocarbon fuel to a value sufficient to prevent a substant-ial amount of static electricity accumulation.

Suitable examples of glycol ethers which are employable in the additive of this invention include, among others, the following: methyl ether of ethylene glycol (methyl Cellosolve); ethyl ether of ethylene glycol (ethyl Cellosolve); butyl ether of ethylene glycol (butyl Cellosolve); methyl ether of diethylene glycol (methyl carbitol); ethyl ether of diethylene glycol (ethyl carbitod); butyl ether of dieth ylene glycol (butyl carbitol); methyl ether of triethylene glycol; ethyl ether of triethylene glycol; phenyl ether of ethylene glycol; tolyl ether of ethylene glycol; phenyl ether of triethylene glycol; tolyl ether of triethylene glycol; diethylene glycol; triethylene glycol; and tetraethylene glycol.

A presently preferred group of glycol ethers suitable for use in the practice of the invention are those having the formula R(OCH CH OH wherein: R is selected from the group consisting of methyl, ethyl, propyl, and butyl groups, and x is an integer of fro-m 1 to 4. The most preferred glycol ethers are those of the above formula wherein R is methyl or ethyl and x is 1 or 2.

Suitable examples of saturated acyclic polyhydroxy alcohols include the following: 1,2-dihydroxypropane; 1,3- dihydroxypropane; glycerol; 1,2,3-trihydroxybutane; 1,2, 4 trihydroxybutane; 2 (hydroxymethyl)-1,3-dihydroxypropane; erythritol; pentaerythritol; l,2,3,4-tetrahydroxy pentane; 1,2,3,5 tetrahydroxypentane; l,2,4,5-tetrahydroxypentane; 2-(hydroxymethyl)-l,3,4-trihydroxybutane; and l,2,3,4,S-pentahydroxypentane.

A presently preferred group of polyhydroxy alcohols are: glycerol; 1,2,3-trihydroxybutane; 1,2,4-trihydroxybutane; and erythritol. Glycerol is the presently most preferred polyhydroxy alcohol.

In general, the combination of the glycol ether and the saturated acyclic polyhydric alcohol is present in the hydrocarbon fuel in the range of 0.01 to 1.0 volume percent based on fuel, preferably 0.01 to 0.5, more preferably 0.05 to 0.2 volume percent. In addition the ratio of the alcohol to the ether is such that there is present 0.4 to 49 volume percent alcohol and 99.6 to 51 volume percent ether, preferably 0.5 to 40 volume percent alcohol and 99.5 to 60 volume percent ether, even more preferably 0.7 to volume percent alcohol and 99.3 to 90 volume percent ether.

A preferred combination useful as an additive to a hydrocarbon fuel is methyl Cellosolve, glycerol and stearamidopropyldimethyl(beta-hydroxyethyl)ammonium nitrate.

The components of the additive may be added to the hydrocarbon fuel in broad ranges of concentration. Preferably, the nitrogenous compound is persent in an amount win the range of 0.05 to 500 weight parts per million based on fuel, preferably 4 to 100 weight parts per million.

The above components may be dispersed in the hydrocarbon fuel prior to injection into the storage tank, either individually or preblended as a compatible composition or added to the storage tank, so long as they are homogeneously dispersed or distributed throughout the hydrocarbon fuel. The additive is easily dispersed in the fuel in any conventional manner such as stirrer-equipped tanks, pipe line feed and the like.

Any suitable type of hydrocarbon fuel can be employed in the practice of the invention. The hydrocarbon fuels in which the additive of the invention may be employed include those boiling between about 75 and about 750 F., at one atmosphere pressure, particularly petroleum distillate fuels boiling in that range. Such fuels include gasolines, aviation turbojet fuels, kerosenes, diesel fuels and heating oils. Gasolines, as referred to herein, are mixtures of volatile hydrocarbons boiling between about 75 F. and about 450 F. as determined by ASTM D-86-56 and presently defined by ASTM Specification D-9 10-57-T and D-439-58T. Such gasolines frequently contain various beneficial additives such as antiknock agents, scavenging agents, antioxidants, dyes, anti-icing agents and solvent oils in total additive concentrates up to about 5 percent by weight. volatile hydrocarbons boiling in the range between about 100 F. and about 600 F. and are presently defined by US. Military Specifications MlL-J5624, MILF-25524 and MILF25558. Diesel fuels, as referred to in connection with the invention in general, boil between about 250 F. and about 750 F. and are covered by ASTM Specification D-975-53T. Heating oils, as the term is used herein, include both kerosenes and burning oils falling within Grades 1 and 2 of ASTM Specification D-396-48T. As pointed out hereinbefore, the additives of the invention are particularly useful in jet aviation fuels. They may, however, also be employed in solvent naphthas, transformer oils and other hydrocarbon oils boiling between about 75 F. and about 750 F.

Thus, while the invention has been described with reference to jet engine fuels, e.g. JP-3, JP-4 and JP-S, the invention is not so limited. As used herein, the terms jet engine and jet engine fuel refer to and include turboprop, turbojet, ramjet and pulse jet engines and fuels designed to be used in said engines.

The additive of this invention is particularly adaptable for operating a jet engine which encounters subfreezing temperatures, said engine being equipped with a fuel supply system subject to being obstructed by ice formation Aviation turbojet fuels comprise mixtures of a at subfreezing temperatures due to the presence of water in the fuel, said fuel supply system also being subject to static electricity accumulation due to the use of a hydrocarbon fuel of undesirable electrical conductivity characteristics. In such use my invention resides in the step of passing a liquid hydrocarbon fuel through said fuel supply system to the combustion zone, said fuel containing the nitrogenous compound, glycol ether and polyhydroxyalcohol additive of this invention as hereinbefore described.

The invention will now be illustrated by the following specific embodiments.

The JP-4 fuel used in the following examples had the following physical properties:

Reid vapor pressure 2. 9 A.P.I. 56. 4 Distillation F.) I.B.P. 125 60 326 5 169 340 40 2B0 Rec 99 5O 304 Res I Said fuel complied fully with all other specifications for a JP-4 jet fuel, including the freezing point specification maximum of 76 F. As is known to those skilled in the art, this freezing point specification is provided to insure that plugging of the fuel system will not occur due to freezing of the fuel itself at the low temperatures existing at the high altitudes at which jet aircraft operate.

EXAMPLE I Interfacial tension, dynes/cm.

Fuel additive Commercial antistatic agent O," 80 ppm. A +G" (80 ppm.) Commercial additive D, 80 ppm. A |-D (S0 p.p.m.)

1 0.10 volume percent based on fuel of a mixture of 90 parts by volume of methyl Cellosolve and 10 parts by volume of glycerol.

The data in the preceding Table I demonstrate the synergistic effect of the stearamidopropyldimethyl(beta-hydroxyethyl)ammonium nitrate and the preferred anti-icing agent which comprises methyl Cellosolve and glycerol. It is obvious that the components coact so as to produce an interfacial tension in the fuel which is substantially higher than that obtainable with the stearamidopropyldimethyl (beta-hydroxyethyl)ammonium nitrate by itself. This is most surprising since one would expect the interfacial tension of the fuel containing the combined additives to be decreased by an amount which is approximately the sum of the decrease due to the stearamidopropyldimethyl(betahydroxyethynammoniurn nitrate and the decrease due to the anti-icing agent when used individually. It is to be noted that no such coaction with the anti-icing agent exists with the two control additives.

EXAMPLE II Runs were made to determine the effect of the concentration of stearamidopropyldimethyl(beta-hydroxyethyl) ammonium nitrate on the interfacial tension values, determined as described in Example I.

8 EXAMPLE 1v Since the water separability data in Example I was Table 11 based on interfacial tension values, additional runs were made using an accepted device closely approaching the Run Nu PPM B 1 1 Interracm tension, actual conditions facing a fuel being used in a jet engine. dyHeS/cm- The data in Table IV was obtained using a Water Separorneter, Model 1104, Emcee Electronics, Inc., Clay- 28-3 mont, Delaware. 4 1 The principle of the device is essentially that of full g8 g2 10 scale fuel handling equipment wherein jet fuel is pumped through a filter containing a fiberglass filter element which 1 See Example I coalesces the minute particles of water which may be dispersed in the fuel into larger droplets which are then data clearly demonstrate the operablhty of the capable of settling out and being removed from the fuel. Composltlon Over a Wlde range- Two liters of JP-4 hydrocarbon jet fuel were emulsi- EXAMPLE 111 fited wilth mll. offiwater at 75 t? 85 F. and pumped t roug a erg ass ter at rates 0 30 40 50 70 90 The electrical conductivity of a hydrocarbon fuel JP-4, 1 1 containing different additives was determined 1n order to 331 g 23 ;223:12 r fi fiiif gg g 3 2 1 demonstrate the effectiveness of the preferred composi- 20 tered fual is measurd by a photocell pThus i effect of fion of the invention with regard to its ability to prevent the additive on the separability of water from the fuel is iififigiifgfgg gg ggg gg gg ig giggz i i i i fi determined. One instrument reading is made on a 0 100 11'1110/ cm Electrical conductivity was determined on apscale of g resulting a rgadmgs are average to yie a va ue nown as ater eparagg suclias desfcrs'liaeq l f p f i i g g 25 tion Index. Fuel compositions yielding high numerical ta t g E Ions S 5:??? 6 r0 eum t 5 g values are therefore superior to fuels yielding low numeri g g fg g g gg 1 in gfi z g g fi z i ical values from the standpoint of water separability. ber 12, 1957. Table IV Table I Run Fuel additive Water sepaia No. tion index .Run Fuel additives Specific con- N o. ductivlty, 1 None 100 mho/cm. 2 A1, anti-icing agent 2 100 35 3 B, stearamidopropyldimethyl (betahydroxy- 2 67. 2 Nmw 2 lxlo 4 Aethygalnonmni nitrate, 20 p.p.m. 2 99 5 A anti-ieing agent .III 2 1 10 511:1: oenlneremi 'ri tis ieiietiht'"(B 165515. 1: 6418 Commercial antistatic agent C 40 p.p.m-.-- 0.92 10- 6 A1 3" 40 p p m) 2 62 5 40 .m.+A 2.78X10'i3 I. B, 4 p.p.m.-l-A 4.73 10 40 3 Average of 4 13 16 ppm 3 OOX1O 1U Amount recommended by manufacturer. 16 1021mm) It is to be noted that synergism of the anti-icing agent a f and stearamidopropyldimethyl(beta hydroxyethyDam- .2 E555 fg f fiilg runs. monium nitrate with respect to Water separability is again demonstrated. One would expect an additive effect so ff .2 to 3 'fi g a that the value would be 67.2 instead of 99.5 as obtained. amoun s o e S eemml Opropy y It is to be noted that this is the case with C when added 'droxyethyl)ammon1um nitrate added to the hydrocarbon to A (Run N0 6) fuel is sufficient to increase the conductivity to the desired EXAMPLE V level. It is further seen that a combination of the stear- .amidodi ropyldimethyl(beta-hydroxyethyl)ammonium ni- The synergistic eifectof a mixture of methyl Cellosolve trate and the preferred anti-icing agent is also satisfactory. and steafainldopfopyldlmetllyl(beta y y y l In addition, the ombination of the stearamidodipropyldini m filtrate Was investigated as to specific conducmethyl(beta-hydroxyethyl)ammonium nitrate and the tivity and water separability. The following data were anti-icing agent display conductivities which are greater Obtained on JP-4 jet fuel in the same manner as hereinthan one would expect from the effect each gave indibefore described in Example III.

Table V Run Fuel additive Specific conductivity, Water separation index No. mho/cm.

1 None 6.94 10 (Av. 0i3runs). 100. 2 0.1 vol. percent methyl Cellosolve 1.s5 10- (Av. 0f 2runs). 100 (Av. of 2 runs). 3 20 stiegramidopropyldirrethyl (beta- 2.08X10-11 (Av. of 2runs) 67.2 (Av. of 4 runs). 4 0.1ol $enrhilfle3ljdb27fiib p.p.m. 4.77 10- (Av. of 2rur1s) 81.0 (Av. of 2runs).

il fifiefififihfifiud nitrate).

It will be noted that this specimen varies slightly in conductivity from another specimen of the same fuel used in Example III. This variance is believed due to lack of instrument sensitivity at this low level of con ductivity.

vidually. Thus, there is a synergistic effect for the antiicing agent and the stearamidodipropyldimethyl (beta-hydroxyethyl)ammonium nitrate with respect to conductivity as well as water separation,

fuel.

It will be seen from the above data that the addition of methyl Cellosolve by itself to the hydrocarbon fuel does not substantially improve the specific conductivity of the Although the addition of the nitrogenous cornpound does improve the anti-static properties of the fuel to Within an acceptable range, it is to be noted from Run No. 4 that the combination of methyl Cellosolve and the stearamidopropyldimethyl (beta-hydroxyethyl) ammonium nitrate more than doubles the specific conductivity of the run without the methyl Cellosolve.

It is also to be noted that the combination of the glycol ether and the nitrogenous compound serve to substantially increase the probability that the Water may be removed from the hydrocarbon fuel by conventional filters and the like.

While certain examples, structures, compositions and process steps have been described for purposes of illustration the invention is not limited to these. Variation and modification within the scope of the disclosure and the claims can readily be eifected by those skilled in the art.

I claim:

1. A liquid hydrocarbon fuel having a boiling point in the range of about 75 to about 750 F. and having a conductivity of 1x to 1 10 mho/cm. containing an additive consisting essentially of (1) from 0.01 to 1.0 volume percent based on fuel of a blend of (A) 99.6 to 51 volume percent of ethylene glycol monomethyl ether, and (B) 0.4 to 49 volume percent of glycerol and (2) 10 from 0.05 to 500 weight parts .per million parts of fuel of stearamidopropyldimethyl(beta-hydroxyethyl ammonium nitrate, said (2) being present in said fuel in an amount sufiicient to synergistically increase the electrical conduc tivity of said fuel to at least 1 l0 mho/ cm.

2. An additive useful in a liquid hydrocarbon fuel, said fuel having a boiling point in the range of about to about 750 F. and having a conductivity of l 10- to 1 l0 mho/cm., said additive consisting essentially of (1) from 20 to 2000 weight parts of a blend of (A) 99.6 to 51 volume percent of ethylene glycol monomethyl ether and (B) .4 to 49 volume percent of glycerol, and (2) one Weight part of stearamidopropyldirnethyl(betahydroxyethyl) ammonium nitrate.

References Cited by the Examiner UNITED STATES PATENTS 2,589,674 3/1952 Cook et al 252-8.8 X 2,626,876 1/1953 Carnes 2528,75 X 2,901,430 8/1959 Chiddix et al. 44-66 X 3,027,246 3/1962 Bartlett 44-66 3,032,971 5/1962 Shotton 4477 X 3,048,539 8/1962 Kocay et al 2528.8

DANIEL E. WYMAN, Primary Examiner. 

1. A LIQUID HYDROCARBON FUEL HAVING A BOILNG POINT IN THE RANGE OF ABOUT 75 TO ABOUT 750*F. AND HAVING A CONDUCTIVITY OF 1X10**-12 TO 1X10**-15MHO/CM. CONTAINING AN ADDITIVE CONSISTING ESSENTIALLY OF (1) FROM 0.01 TO 1.0 VOLUME PERCENT BASED ON FUEL OF A BLEND OF (A) 99.6 TO 51 VOLUME PERCENT OF EHTYLENE GLYCOL MONOMETHYL ETHER, AND (B) 0.4 TO 49 VOLUME PERCENT OF GLYCEROL AND (2) FROM 0.05 TO 500 WEIGHT PLARTS PER MILLION PARTS OF FUEL OF STEARAMIDOPROPYLDIMETHYL(BETA-HYDROXYETHYL) AMMONIUM NITRATE, SAID (2) BEING PRESENT IN SAID FUEL IN AN AMOUNT SUFFICIENT TO SYNERGISTICALLY INCREASE THE ELECTRICAL CONDUCTIVITY OF SAID FUEL TO AT LEAST 1X10**-11MHO/CM. 